[libgcj] warning patches

[Tom Tromey]

>>>>> "Jason" == Jason Merrill <jason@redhat.com> writes:

Jason> The first one is pretty obvious.  The second is GCC-specific,
Jason> but I figure that's OK since the C++-Java interface is pretty
Jason> GCC-specific.

Yes, we're happily free to use gcc extensions as we like.

Jason> Also, why not just use sprintf?

Historically we've avoided *printf so that, in theory, we could build
an embedded libgcj as small as possible.  In practice it hasn't seemed
to help much, but we still mostly follow the rule.  Perhaps it is
wishful thinking.

Jason> OK to check in?

Definitely, thanks.

Tom